Q&As

Below are just some of the regular questions we get asked about our fire retardant treatments for timber. Should you need more detail from the answers supplied or have other questions, please contact our customer support services on 01977 714118 / 714124 / 714139 or timberprotectionadvice.ukca@lonza.com

1. What is the difference between DRICON and NON-COM Exterior fire retardant treatments?


2. What accreditations does DRICON hold?


3. What assurance does the BBA accreditation for DRICON give me as a specifier?


4. What accreditations does NON-COM Exterior hold?


5. What is the difference between WPA 'Listed' status and WPA 'Approved' status treatments?


6. Are there model specifications for Lonza fire retardant treatments?


7. What are Euroclasses and why are they replacing the old Class 1 / Class 0 standards?


8. How many new Euroclass Classifications are there for fire performance and which are relevant to timber?


9. Are these new Euroclasses as good as the old Class 1 / Class 0?


10. Building Control want evidence that the fire treated timber / plywood I am supplying will be Euroclass B / Euroclass C compliant. What documentation do I need?


11. I have a specification that asks for a FR5 fire retardant treatment. What does this mean?


12. What timbers can be treated with NON-COM Exterior and DRICON?


13. Does DRICON or NON-COM Exterior treatment alter the appearance of fire treated timber / plywood?


14. What do I need to consider when specifying a quality fire retardant treatment for timber / plywood to ensure that I have a quality product that is fully compliant and durable?


15. I urgently need to achieve a fire performance to my timber / plywood which is not yet on a building. Impregnation will take too long. What do I do?


16. What are the benefits of factory controlled impregnation treatments over brush/spray surface applied FR coatings?


17. How do fire retardant treatment impregnation treatments work?


18. What fire performance is commonly required for external timber cladding?


19. If the fire treated cladding timbers or plywoods are cut on-site do they need any extra protection?


20. Can I re-profile my cladding once treated?


21. Can you fire treat veneered plywood?


22. Do I have to preservative treat exterior timbers as well as fire treat them?


23. Can I achieve 30 or 60 minute fire resistance with DRICON and NON-COM Exterior?


24. What fire retardant treatment is recommended for my cladding battens?


25. Can you fire treat green oak?


26. Do I need to increase my material wastage allowance to take into account changes in timber properties after FR treatment?


27. Can you recommend a decorative coating for use with DRICON fire retardant treated timber or plywood?


28. Is there a recommended decorative coating for NON-COM Exterior timber?


29. Is CE Marking of fire retardant treated timbers required?


30. Modern school building projects specify timber extensively. Are the Lonza fire retardant treatments suitable for these types of projects?


31. Does Lonza Wood Protection still process timber/plywood to Class 1 or Class 0 for material to be used in permanent construction?


32. I have a specification of B, s1 d0. What does it mean?


33. Can Lonza fire retardant treatments be applied to timber for use on Rail and London Underground projects?


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1. What is the difference between DRICON and NON-COM Exterior fire retardant treatments?

DRICON is a water based, Humidity Resistant (HR) type formulation that is applied by Lonza Wood Protection at our own treatment facility at Castleford under controlled conditions in a high pressure impregnation plant, commonly followed by kiln drying to return the timber to an acceptable or specified moisture content.

 

DRICON treated timbers/sheet materials are suitable for:

  • all interior applications.

Typical end uses for DRICON treated material would be internal building timbers and lining material, internal timber cladding, internal staircases, scaffold boards, rail and transport industry projects.

 

NON-COM Exterior is a water-based, polymer resin Leach Resistant (LR) type formulation. It is applied to timber by Lonza Wood Protection at our own treatment facility at Castleford using a high pressure impregnation process followed by kiln drying which involves a short high temperature curing process at the end of the kilning cycle to 'lock' the treatment into the timber and return the timber to an acceptable moisture content.

NON-COM Exterior treated timbers are suitable for full exterior and severe damp applications, without the need for a protective coating.

 

Typical end uses for NON-COM Exterior treated material are:

  • exterior cladding and exposed timber structures.

  • cedar shingles, ridges and shakes.

 

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2. What accreditations does DRICON hold?

  • The ONLY fire retardant treatment for timber in the UK with BBA Agrement accreditation.

  • UK Wood Protection Association (WPA) approved status type HR (humidity resistant) fire retardant product.

  • Quality accredited through the UK Wood Protection Association FR Benchmark certification scheme

  • Fully tested by Exova Warrington Fire ReseLonza with independent Euroclass Classification Reports for each timber species and timber thickness, for use with or without air gaps - EN 13501-1.

  • Fully approved for use in London Underground - meets the requirements of London Underground Standard 1-085 'Fire Safety performance of Materials'.

  • Certification of the fire retardant treated timber as a Sustainable Building Material by the Dutch Institute of Building Biology and Building Ecology.

  • Independently assessed by Chiltern International Fire in the 6 storey timber frame TF2000 (Staircase 2001) study and found to satisfy the functional fire safety requirements of the UK Building Regulations.

  • Recommended by the National Access & Scaffolding Confederation for the treatment of scaffold boards.
     

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3. What assurance does the BBA accreditation for DRICON give me as a specifier?

DRICON is the only fire treatment for timber in the UK to have achieved BBA certification.

The BBA Certificate shows how DRICON demonstrates full compliance with Building Regulations across the UK.

BBA approval involves considerable commitment and expenditure by the manufacturers who hold it. Over 25 years ago DRICON was first submitted for extensive testing by the British Board of Agrement (BBA), the UK's major approval body for new construction products. The BBA logo validates the claims we make for the performance and durability of our DRICON treatment and unequivocally demonstrates its fitness for purpose.

In conjunction, on -going inspection of our manufacturing site by BBA confirms the consistency of our production year after year after year giving specifiers complete assurance when selecting DRICON treatment.

 

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4. What accreditations does NON-COM Exterior hold?

  • The ONLY fire retardant treatment for timber in the UK accepted for use by NHBC for external timber claddings. Durability data for NON-COM Exterior supports a service life in excess of 30 years in terms of fire performance.

  • UK Wood Protection Association (WPA) approved status type LR (leach resistant) fire retardant product for the protection of exterior timbers

  • Quality accredited through the UK Wood Protection Association FR Benchmark certification scheme.

  • Fully tested by Exova Warrington Fire ReseLonza with independent Euroclass Classification Reports for each timber species and timber thickness, for use with or without air gaps - EN 13501-1.

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5. What is the difference between WPA 'Listed' status and WPA 'Approved' status treatments?

Both DRICON and NON-COM Exterior treatments hold WPA 'Approved' Status.

WPA criteria to achieve a 'Listed' status are far less stringent than those for 'Approved' status.

WPA criteria to achieve 'Listed' status:

  • Manufacturers declaration ONLY of the hygroscopic and leach resistance (where applicable) nature of the FR product.

  • No third party evaluation of fire data required - fire certification is the only way a manufacturer can demonstrate that the relevant fire testing has been done by species but no certification whatsoever is assessed to achieve 'Listed' status.

  • No third party evaluation of other ancillary properties required.

WPA criteria to achieve 'Approved' status:

  • Independent panel approval, with rigorous assessment of:

- fire performance and classification reports, including smoke

- hygroscopicity

- leach resistance (where applicable)

- key ancillary properties such as corrosion, strength, preservation properties

Why choose a WPA 'Listed' fire treatment when you can have the assurance that goes with selecting WPA 'Approved' fire treatment?

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6. Are there model specifications for Lonza fire retardant treatments?

Both DRICON and NON-COM Exterior are listed in NBS Plus and RIBA Product Selector - see our Specification Zone for more information.

In addition we offer model specifications for DRICON or NON-COM Exterior treated timbers - documents available on request.

 

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7. What are Euroclasses and why are they replacing the old Class 1 / Class 0 standards?

Under the Construction Products Regulation introduced in July 2013 there is a move towards the European harmonisation of Standards for the fire retardant treatment of timber and plywood, with Euroclass B and Euroclass C replacing the old standards Class 0 and Class 1 respectively.

To achieve either a Euroclass B or C Specification, timber/plywood is tested to EN 13823:2002 (SBI or Single Burning Item Test) and EN ISO 11925 (Ignitability Test).

The SBI test is key and records parameters relating to the rate of fire growth, flame spread, heat release and smoke emission.

These test results are assessed in accordance with EN 13501-1 (Fire Classification of Construction Products and Building Elements) taking into account the presence or absence of an air gap behind the treated material and the fire characteristics of backing materials and a Euroclass Classification is assigned accordingly.

The same set of tests are conducted for both a Euroclass B and Euroclass C fire performance. However the thresholds for compliance in relation to SBI criteria are more stringent for Euroclass B than for Euroclass C. Therefore, by definition, if timber/plywood conforms to Euroclass B then it also conforms to Euroclass C.

In England and Wales, the fire requirements for buildings are dealt with by Approved Document Part B to the Building Regulations.

For timber and plywood in permanent construction, Euroclass B has now replaced Class 0 and Euroclass C has now replaced Class 1.

PLEASE NOTE: It is not possible to treat to a National Class and sell as a European Class or vice versa. For instance, timber treated to Class 0 cannot be sold as Euroclass B.

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8. How many new Euroclass Classifications are there for fire performance and which are relevant to timber?

There are seven Euroclass Classifications for fire performance of different construction materials ranging from A1 & A2 through to F. Classifications for timber include B, C, D & E. Euroclasses D & E relate to untreated timber. Fire retardant impregnation to timber / plywood can elevate timber from Euroclass D (essentially untreated) to Euroclass C or Euroclass B to give the material in question compliance with the requirements of UK Building Regulations depending upon the location of the material within the building.

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9. Are Euroclasses as good as the old Class 1 / Class 0?

The simple answer is that Euroclasses are underpinned by more up-to-date test methods compared to the old British Standards and trying to compare old and new is the wrong approach. Class 1 involved a measure of the Surface Spread of Flame (SSF). Class 0 included a measure of SSF and heat release. The Euroclass SBI test measures a wider scope of fire critical factors than the old Class 1 /0 tests, namely heat release, fire growth rate, smoke levels and flaming droplets. Euroclasses are more robust.

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10. Building Control want evidence that the fire treated timber / plywood I am supplying will be Euroclass B / Euroclass C compliant. What documentation do I need?

Lonza Wood Protection issues a Fire Treatment Certificate upon despatch of an order which itemises customer name and order details. Generally this is what is presented to Building Control.

However, our recommendation is that a species/thickness specific Euroclass Classification Report, issued by UK independent fire test house such as Exova Warrington Fire, is also requested from the treater of the timber / plywood.

FULL COMPLIANCE = TREATMENT CERTIFICATE + CLASSIFICATION REPORT

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11. I have a specification that asks for a FR5 fire retardant treatment. What does this mean?

The UK Wood Protection Association (WPA) has a number of commodity specifications relating to fire retardant treatment. Each of these commodity specifications ONLY classifies the end use which is then used as a guide to select the appropriate fire retardant treatment.

THEY DO NOT IDENTIFY WHAT FIRE PERFORMANCE IS REQUIRED FOR THE PROJECT IN QUESTION.

Exterior timber cladding is usually assigned an FR5 commodity specification.

The list of commodity specifications is as follows:

FR1 - Non load bearing dry interior use

FR2 - Load bearing dry interior use

FR3 - Interior use with a Relative Humidity >75%

FR4 - Weather protected exterior use

FR5 - Weather exposed situation

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12. What timbers can be treated with NON-COM Exterior and DRICON?

NON-COM Exterior - We hold an extensive portfolio of certification in terms of timbers we can NON-COM Exterior treat, from typical cladding timbers such as cedar, lLonza and Thermowood to more unusual species such as cumaru.

DRICON - We hold an extensive portfolio of DRICON certification for plywoods and solid timbers. Typical plywood species include birch and spruce and solid timbers include typical softwoods through to more unusual species.

Download our treatable species guide for more information.

Please give us a call to discuss your project requirements.

 

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13. Does DRICON or NON-COM Exterior treatment alter the appearance of fire treated timber / plywood?

As a general rule:

NON-COM Exterior treated timber looks slightly darker than un-treated timber but will weather down the same as un-treated timber overtime.

DRICON treated timber looks slightly lighter than un-treated timber but will weather down the same as un-treated timber.

Some species have their own specific treatment characteristics. Please contact us to discuss your requirements in more detail.

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14. What do I need to consider when specifying a quality fire retardant treatment for timber / plywood to ensure that I have a quality product that is fully compliant and durable?

There are three keys aspects to consider:

1. CERTIFICATION

To support a Euroclass B or C specification, Classification Reports from an independent notified body according to EN 13501-1 are a key requirement.

The description of the product given in the Classification Report has to be comparable with the specification of the timber to be used in the project.

For example, if a Classification Report refers to Euroclass B, s1, d0 for 25mm thick spruce boards tested without an air-gap on plasterboard, then the product cannot be assumed to confer the same reaction-to-fire performance for:

  • Timbers less than 25mm

  • Alternative species

  • With an air gap

  • Other backing materials deemed to be of higher risk

Key point: Ask the fire retardant treatment company to show / send you the Euroclass Classification Report relevant to the timber species and thickness being specified or treated. Don't just assume that the correct fire testing has been done. Failure to check means you could put your company at risk!!!

All Lonza Wood Protection fire testing is done through Exova Warrington Fire ReseLonza. We hold a wide portfolio of Euroclass Classification Reports to match a wide range of species, thicknesses and end uses.

2. LONG TERM DURABILITY

Whilst initial compliance is a primary consideration, the ability of the fire treatment to remain stable within the timber/ plywood during its service life should also be a fundamental concern for the specifier/ end user.

DRICON - DRICON treated timber/plywood is commonly used internally and is non-hygroscopic ie. it has the ability to resist moisture to relative humidities in excess of 90% without any migration of the fire treatment within the plywood or timber.

The Wood Protection Association (WPA) independently tested DRICON and NON-COM Exterior treated timber after 21 years and demonstrated that fire performance had been maintained during that time.

NON-COM Exterior - The heat curing process involved in the NON-COM Exterior treatment polymerises the organic resins to form insoluble polymer molecules, locked inside the timber cells. The leach resistance of NON-COM Exterior within the treated timber ensures the durability of the fire performance in exterior exposure and severe damp situations. It is the ONLY Approved type LR (leach resistant) treatment in the UK Wood Protection Association (WPA) Manual.

The long term durability of fire performance for NON-COM Exterior treated timber has been confirmed to be maintained following exposure to the accelerated weathering regime detailed in American Standard Test Method ASTM D2898. It is also classified in accordance with Nordic Test method NT Fire 054 as a Durability of Reaction to Fire "DFR Class EXT" fire retardant, meeting the requirements of Nordic standards for use in all exterior applications.

The treatment within the timber is non-hygroscopic - i.e. it does not absorb water from the air; nor does it give rise to efflorescence. However, the hygroscopic nature of timber will remain.

3. QUALITY ACCREDITED APPLICATION

The core philosophy of Lonza Wood Protection is 'Duty of Care'.

Day in day out our aim is to deliver quality fire treated products underpinned by rigorous on going quality assurance. Lonza Wood Protection is the ONLY WPA approved and listed treater with ISO 9001 and ISO 14001 accreditations which gives specifiers, merchants and contractors alike the assurance that we consistently send out fire retardant treated boards and timbers that have full compliance to the Euroclass required.

At Lonza Wood Protection each timber species is tested individually to determine the exact fire treatment requirements and the fire retardant product retention needed for any given fire performance. This is not always the case with other fire retardant treatment suppliers.

Failure to check the correct fire certification is in place means you could put your company at risk.

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15. I urgently need to achieve a fire performance to my timber / plywood which is not yet on a building. Impregnation will take too long. What do I do?

Good planning at the outset of a project to allow time for impregnation treatment (commonly 4 weeks for treatments between 20-30m3) would be the first recommendation. Machining and delivery lead times also need to be taken into consideration.

A coating tends to be considered when lead time is an issue but it is important to understand the benefits of a durable, quality, factory applied impregnation treatment against the potential issues associated with a 'quick fix' surface applied FR coating.

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16. What are the benefits of factory controlled impregnation treatments over brush/spray surface applied FR coatings?


 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

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17. How do fire retardant treatment impregnation treatments work?

The impregnated fire treatment lives passively in the timber until a fire strikes.

When untreated timber burns the natural volatile tars & gases present in timber combust which generates a high level of heat & smoke emission resulting in a high rate of fire growth & a degree of char formation.

A fire retardant treatment modifies the nature of the burning process.

The heat from the fire causes rapid dehydration of the timber. This water dilutes & cools the volatile gases which in turn reduces the rate of fire growth & heat emission.

There is also a high level of char formation which is insulating & contributes to the reduced rate of fire growth.

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

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18. What fire performance is commonly required for external timber cladding?

Generally timber cladding within 1 metre of a boundary is treated to Euroclass B fire performance with NON-COM Exterior to comply with the requirements within UK Building Regulations.

 

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19. If the fire treated cladding timbers or plywoods are cut on-site do they need any extra protection?

Providing that the cut edges are butt jointed no additional treatment is required to the cross cut ends of cladding of standard thicknesses or for plywood after cross cutting.

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20. Can I re-profile my cladding once treated?

No. Treated timbers can be cross cut providing the cut ends are butt jointed but they cannot be rip sawn or re-profiled after treatment.

Removal of timber via re-profiling would result in removal of fire treatment and hence the fire performance.

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21. Can you fire treat veneered plywood?

We do not recommend fire retardant impregnation treatment of pre-veneered plywood. The veneers are prone to blistering / delamination at the point of treatment.

However there are other options available. Please contact us directly to discuss your requirements further.

 

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22. Do I have to preservative treat exterior timbers as well as fire treat them?

As a secondary mode of action, NON-COM Exterior treatment offers a high level of biological resistance to fire treated exterior timber and therefore additional preservative treatment is not required.

Also, clean, virgin timber must be supplied for fire treatment.

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23. Can I achieve 30 or 60 minute fire resistance with DRICON and NON-COM Exterior?

In short no.

We offer fire retardant impregnation treatments that upgrade the fire performance of timber to achieve either a Euroclass B or Euroclass C fire performance.

Euroclass compliant timber retards the growth/propagation of a developing fire by limiting the amount of heat generated, the overall fire growth rate, the level of smoke production & flame spread in line with parameters defined within Euroclass Standards that are fully accepted within UK Building Regulations.

The key objective of a Euroclass specification is to retard fire growth to give people time to evacuate a burning building.

Note: Euroclasses are not a time rated fire performance.

Fire Resistance is a time related concept (30 or 60 mins typically) & commonly refers to the ability of a material or item to resist the passage of fire e.g. a 30 minute fire door will resist burn through for a minimum period of 30 mins the ability of timber to remain structurally load bearing after a defined amount of burning time.

 

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24. What fire retardant treatment is recommended for my cladding battens?

For closed cladding, where the battens will never be exposed to direct wetting, either DRICON or NON-COM Exterior treatment can be used.

For open cladding e.g. rainscreen, where the design of the cladding means the battens will be exposed to direct wetting from rain or snow, only NON-COM Exterior treatment should be used.

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25. Can you fire treat green oak?

The simple answer is no. Timber must be kiln dried before treatment.

Commonly kiln dried cladding is supplied for fire treatment with a moisture content of 13-19%. The nature of modified timbers is that they are manufactured with lower moisture contents typically ranging 6-10%.

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26. Do I need to increase my material wastage allowance to take into account changes in timber properties after FR treatment?

For the majority of species, customers should supply a minimum 5% extra material with each order to allow for kiln degrade, kiln samples and moisture content samples.

However, some species will require more of a wastage factor than others. We strongly recommend that you contact us directly to discuss project specifics.

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27. Can you recommend a decorative coating for use with DRICON fire retardant treated timber or plywood?

For decorative coatings for DRICON treated timbers Lonza Wood Protection now offers DRYWOOD FIRESTAIN in a range of colours and finishes for use on DRICON interior treated timbers.

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28. Is there a recommended coating for NON-COM Exterior timber?

For decorative coatings for NON-COM Exterior treated timbers Lonza Wood Protection now offers DRYWOOD WOODSTAIN in a range of colours and finishes for use on NON-COM Exterior treated lLonza cladding timbers.


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29. Is CE Marking of fire retardant treated timbers required?

As part of the Construction Products Regulation the CE marking of permanently installed construction timbers is now required.

Contact Lonza Wood Protection directly for further guidance, if required.

 

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30. Modern school building projects specify timber extensively. Are Lonza fire retardant treatments suitable for these types of projects?

Both DRICON and NON-COM Exterior have been widely used to protect interior and exterior timbers used in recent school buildings to provide a tried, tested and trusted long term fire protection in such an important environment.

View our leaflet on recent school building projects.

 

 

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32. I have a specification of B, s1 d0. What does it mean?

'B' relates to the fire performance required for Building Regulation compliance, ie. EUROCLASS B.

's' relates to the level of smoke emission recorded in the SBI ( Single Burning Item test). s1, s2 and s3 are the three levels that can be achieved, with s1 being the lowest level of smoke and s3 being the highest.

'd' relates to the level of flaming droplets recorded in an SBI test with d0 being the best level achieved and d2 being the worst.

Therefore: B, s1 d0 means treated to Euroclass B, minimum smoke emission, minimum flaming droplets.

A Euroclass Classification Report will list both the 's' and 'd' levels achieved for each material tested.

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33. Can Lonza fire retardant treatments be applied to timber for use on Rail and London Underground projects?

Yes, DRICON is fully approved for use in London Underground - meeting the requirements of London Underground Standard 1-085 'Fire Safety performance of Materials'. Treatments are to Euroclass B in accordance with EN 13501-1.

Birch plywood intended for flooring in rolling stock can be treated to either EN 45545-2 or to Class 1 BS476-7.

We would recommend you contact Lonza directly to discuss species specific certification details prior to specification.

 

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